Semiconductor memory devices, including flash memory, typically utilize memory cells to store data as an electrical value, such as an electrical charge or voltage. A flash memory cell, for example, includes a single transistor with a floating gate that is used to store a charge representative of a data value. Increases in storage density have been facilitated in various ways, including increasing the density of memory cells on a chip enabled by manufacturing developments, and transitioning from single-level flash memory cells to multi-level flash memory cells, so that two or more bits can be stored by each flash memory cell.
A drawback of increasing storage density is that the stored data is increasingly prone to being stored and/or read erroneously. In order to limit errors, a default reading threshold voltage for flash memory may be adjusted to compensate for deviations in the voltage distributions of the flash memory cell due to electrical fluctuations, defects in the memory cell, operating conditions and cell history. However, in some cases, successive adjustments to the default reading threshold voltage may lead to further errors.